You think the functionality of Facebook compares equally to that of Reddit computational-wise? I mean, I know neither is the most complicated thing ever, but does Reddit even allow photos anywhere besides thumbnails? Does Reddit find things only specific to your account and show you a list of friends and their content you are allowed to see (or even something vaguely similarly complicated)? I also highly doubt that Facebook counts all of the ajax-goodness it delivers as pageviews. I could really go on for a long time (widgets, Facebook connect, Facebook Apps API...) about the huge differences that you glazed over since it's using PHP for the frontend.
No, I think looking at Facebook's numbers, figuring roughly 2 pageviews/server, and then looking at reddits numbers (at roughly 10 pageviews/server) and saying "reddit's setup seems reasonable" makes it a good comparison. It's all just hand waving, but I don't mind using that comparison to put reddit's numbers in perspective.
All of the math is just wacky in the post though - he's comparing peak pageviews/sec/server to Facebook's pageviews/sec/server for a month. Reddit's pageviews/sec/server is 2 using 163 pageviews/sec and 80 servers.
Facebook also doesn't count all webserver HITS as pageviews, whereas most of Reddit's do count.
Beyond that, pageviews for Facebook may eat more resources (CPU/RAM) than Reddit on average due to photo uploading and other misc. things on Facebook. This means a server is working harder at 2pageviews/sec/server for Facebook.
> but does Reddit even allow photos anywhere besides thumbnails?
How is that even relevant? Images cost in bandwidth, not in computing power.
> Does Reddit find things only specific to your account
Uh yes, on every single submission and comments. The admins clearly stated that what used the most resources was the voting system. As well as every single user (whether you marked them as friends) and the list of links itself, which is extracted from the user's own list of reddits.
There is barely anything on a logged in user's page which isn't at least in part specific to that user's account.
> I could really go on for a long time
No, I don't think so, you've been 0/everything so far, it's time to stop.
> How is that even relevant? Images cost in bandwidth, not in computing power.
Sounds like you need to do some STFU yourself, having clearly never come anywhere near this problem domain. Using standard tools to process and resize user-uploaded images can easily soak up all the CPU time and memory you could throw at it.
I recently spent a bunch of time rewriting a client's image processing pipeline fromt the usual O(n)-space ImageMagick crap that loads the full uncompressed image into memory a few times over to be O(1)-space doing streaming downsampling by exploiting the compression implementations of JPEG and PNG. It was more than worth it — even with the PNG implementation being a bit more CPU intensive now, it's a lot nicer having it operate in constant space without fear of swap and the OOM-killer.
